1. Field of the Invention
The present invention generally relates to light source system and image projection system based on wavelength conversion.
2. Description of the Related Art
Multi-color light sequences are often used in stage lighting and image projection display. FIG. 1 shows a conventional system for generating a multi-color light sequence. As shown in FIG. 1, an excitation light 12 from a light source 11 is focused on a color wheel 14 by focusing optics 13. The color wheel 14 includes several segments, which carries different fluorescent materials to convert excitation light to converted light. When the color wheel 14 rotates around the rotation axis 16, driven by driving device 13, these different segments can be exposed in the optical path of the excitation light in turn to generate of multi-color converted light sequence. For example, as shown in FIG. 2, the color wheel 14 including red segment R, green segment G, blue segment B and white segment W can be excited by excitation light 12 and generate a red-green-blue-white color light sequence.
The red-blue-green-white light sequence generated by color wheel 14 shown in FIG. 2 can be applied in the field of white light enhancement: the red, blue and green lights are used to generate color images, while the white light can be used to improve the brightness when data and diagrams are shown. However the above-mentioned light source system has poor unsatisfactory saturation. In other display applications, such as dynamic video display, color saturation of picture is much more important than brightness, so a red-green-blue light sequence without white light is more proper in this situation. Further, two different multi-color light sequences are needed in some stereo projectors, one is for 2D projection display and the other is for 3D projection display. Conventional light source systems and projection devices typically do not provide two different light sequences according to the different working modes.
Therefore a light source system and image projection system are needed to solve the above-mentioned problems.